AUGUSTA, Maine — A group of environmental activists set out Tuesday for Washington with a well-traveled and recycled solar panel that once stood atop President Jimmy Carter’s White House, carrying hopes of persuading the current president to once again generate energy with the sun’s rays.

Environmental author and activist Bill McKibben is leading Unity College students and staff on the solar road trip, with stops planned in Boston and New York en route to Washington.

They’re toting along the Carter-era solar panel in hopes of drumming up support for renewable energy. They also hope to convince President Barack Obama to install new solar panels.

“I can’t think of a clearer win for the president, a better reminder to the legions of young people who worked on his campaign that he is still focused on the future,” McKibben wrote Tuesday in Yale Environment 360, a publication of the Yale School of Forestry and Environmental Studies.

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The solar panels were placed in service on the White House by Carter’s order during the late 1970s as a symbol of commitment to increasing the nation’s use of renewable resources. They didn’t remain for long. They were removed by President Ronald Reagan in the 1980s and put in storage.

Unity College later discovered the panels and obtained them from the government.

In the 1990s, 16 of the panels were used to heat water in the cafeteria serving the college’s 580 students until they reached the end of their functional lives and were taken out of service.

Though they’re worn out, they continue to serve as symbols of environmental awareness.

In August, Unity formally presented one of the solar panels to the chairman of Himin Solar Energy Group of China, which planned to place it in a museum in Shendog province.

Now, McKibben, who appeared last week on “The Late Show with David Letterman” to discuss climate change, is headed to Washington in a trip sponsored in part by the climate change-awareness group 350.org. They’re taking the solar panel in a biodiesel van owned by the central Maine school.

“Over the next several days, they hope to show the White House that there is broad public support to put solar panels back on the White House,” said Jamie Henn of 350.com. Letters have been sent to the White House asking Obama to consider having new panels installed as a renewed symbol of commitment to renewable energy, he said.